1. Field
The present embodiments elates to a system for building and/or handling a tubular string of a drilling device. The drilling device comprises a drill floor and a drilling derrick extending from the drill floor. The drill floor has an extension in a first plane being substantially perpendicular to a first direction. The system comprises a suspension device being fixedly attached to the drilling derrick, wherein a projection of the suspension device, in the first direction, onto the first plane is situated outside the drill floor.
The present embodiments also relate to a drilling device trolley arranged to transport a component to and from a drilling centre of a drilling device. Further, the present invention relates to a use of a drilling device having a drill floor, wherein the drilling device has a suspension device being situated outside the drill floor. Moreover, the present invention relates to a method of adding a tubular member to a tubular string.
2. Description of the Related Art
When drilling in the earth crust, e.g. drilling for natural resources in the form of hydrocarbons like natural gas or oil, it is preferred to achieve rapid and safe drilling. Especially when drilling for hydrocarbons off-shore there are high demands for safety, as leakage of for example oil into the sea could have serious consequences. To improve safety when drilling for hydrocarbons, especially when drilling off-shore, a plurality of systems are used today. Drilling is for example often performed by conveying a drill string through a riser, which riser extends from the drilling device, often being situated at the water surface, down to the bottom.
Moreover, drilling below the bottom often occurs through a blow-out preventer, which on one hand can protect the rest of the drilling equipment against pressure spikes which might occur when a gas pocket with high pressure is encountered during drilling, and on the other hand can be arranged to seal the drilling well if the drilling device, which may be situated on a floating structure, for some reason is drifting away from its drilling position. Further, when the drilling of a well has been finished, a valve system—which is often called “Xmas Tree”—is not seldom attached to the drilling hole, to which valve system conduits may be coupled to lead hydrocarbons to one or more production plants. Both the blow-off preventer and the valve system can be attached to the opening at the bottom of the sea and in these cases the component, i.e. either the blow-out preventer or the valve system, is brought down to the bottom by attaching the component to a tubular string at the drilling device, where the length of the string is successively increased, by connecting tubes to each other at the drilling device, until the component has reached the bottom.
From the abovementioned examples, it is realized that, besides the construction of the tubular string itself, a drilling device, especially a drilling device off-shore, is traditionally used to build and/or handle tubular strings, whose purpose is not directly to perform the drilling itself. Since traditional drilling devices often only have one system for building and/or handling tubular strings, comprising a hang-off device for pipes and a rotary table for rotating and/or holding the tubular string, this has led to that the drilling of an oil well taking long time.
To solve this problem, prior art, e.g. EP 0836 668, suggests that a drilling device of a vessel is provided with two systems, each one comprising a suspension device and a rotary table, for building and/or handling tubular strings. Further, EP 0 836 668 discloses that the drilling device can be provided with means for moving tubular strings between the systems. In this way, parallel activities can be performed by the drilling device, which speeds up the total drilling process. The drilling device according to EP 0 836 668 however becomes fairly large and unwieldy, since the drill floor, to which the rotary tables of the two systems are attached, will for example be substantially larger than the drill floor of drilling devices with only one rotary table. Further, since the drilling derrick is designed to carry two suspension devices, one for each system, the drilling derrick becomes also substantially larger than the drilling derrick of drilling devices with only one suspension device. Since the drill floor and the drilling derrick are often situated high up in a marine structure, this means, apart from the weight of the marine structure increasing, that the centre of gravity is also moved upwards. This is especially critical for floating marine structures, since this movement of the centre of gravity will in the end lead to a reduced deck load capacity of the structure, which in turn can lead to a deteriorated production capacity.